Fungi 



403 



Fig. 248. Stages in the development of the common edible pink-gilled mush- 

 room. Note the underground vegetative body of the plant. 



the hyphae are massed together, although each grows more or less 

 independently of the others. 



In decaying logs or in masses of fallen leaves one often finds 

 cord-like strands of a white, brown, or black color. Not infre- 

 quently these may be traced for considerable distances and found 

 to be connected with a puffball or other mushroom. They are 

 parts of the mycelium, and absorb and conduct food to the fruiting 

 bodies and growing parts. Sometimes these underground strands 

 of the mycelia accumulate food and become greatly enlarged and 

 act as storage organs. In parasitic forms that grow in contact 

 with roots (mycorhiza) they probably absorb and transfer food 

 into the host plant. 



Food supply. When the fungus lives on the soil, its food is 

 derived from the soluble organic materials like sugars, soluble 

 proteins, and amino acids from the plant and animal matter 

 occurring there. Moreover, the fungus may give off enzymes, 

 that act on organic matter and bring about processes that change 

 much of it to soluble substances. This is nothing less than a kind 

 of external digestion, which makes the organic substances capable 

 of diffusing into the cells of the fungus and provides material for 



